UNDERFILLING MATERIAL FOR FLIP-CHIP FITTED PRINTED CIRCUIT BOARDS, A PRINTED CIRCUIT BOARD EQUIPPED THEREWITH, AND A METHOD FOR FILLING RATIO VERIFICATION OF CHIPS WHICH ARE UNDERFILLED THEREWITH

摘要

The invention relates to a method for verifying the distribution and the filling ratio of underfilling materials by means of X-ray inspection, for example, to detect how they are mounted between the chip and the substrate during or after the soldering of chips on a substrate. Said substrate is provided for mechanical support and for supporting the solder bumps. According to the invention, an auxiliary substance or filling substance which absorbs X-rays is incorporated in the underfilling material. The invention makes it possible to reliably test such underfilling stabilizations also during a running production process for fitted printed circuit boards.